Fish community response to reservoir habitat enhancement across multiple spatio-temporal scales

Structural habitat enhancements, such as additions of natural and synthetic fish habitats, are a common management tool used to mitigate the loss of natural physical structure in aging lakes and reservoirs. While habitat additions can concentrate fish, how this concentration effect varies over the age and location of the structure and whether habitat additions increase prey and fish production are poorly understood. I conducted two studies to test for the effects of reservoir habitat additions at different spatial and temporal scales. In the first study, I tested for responses of fish populations and fish prey resources to a whole-reservoir habitat manipulation, where over 1500 trees were added to the littoral zone of a small (22 ha) reservoir, resulting in about 12 times more littoral coarse woody habitat (CWH) compared to pre-habitat enhancement conditions. The CWH addition increased bluegill (Lepomis macrochirus) and largemouth bass (Micropterus salmoides) size structure during the four-year evaluation period but did not increase fish abundance as measured by catch per unit effort (CPUE), prey resources (i.e., zooplankton and macroinvertebrates), and the reproductive output of Lepomis spp. In the second study, I tested whether fish occupancy and relative abundance at 50 synthetic habitat structures (PVC cubes) varied longitudinally within Lake Shelbyville, a 4500-ha reservoir, and with time since deployment, ranging in age from five months to almost five years. Structure location influenced fish relative abundance at PVC cubes, such that catch rates generally decreased from lower to upper reservoir cube locations, with fish present at cubes shifting from primarily crappie (Pomoxis spp.) and sunfishes (Lepomis spp.) at lower reservoir sites to mainly white crappie (Pomoxis annularis) and freshwater drum (Aplodinotus grunniens) at upper reservoir cubes. These studies indicated that understanding the effects of habitat additions at multiple scales is important for the guidance of habitat enhancement programs. For example, observed increases in size structure indicated that habitat additions at the scale of an entire reservoir may enhance fish productivity, while the location of added habitats within a reservoir can shape the types and numbers of fish aggregating at each added habitat patch.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Natural Res & Env Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Fenstermacher, Carly C.

Contributors dc:contributor

• Parkos, Joseph J
• Porreca, Anthony P
• Yu, Zhongjie
• Sass, Greg G

• Reservoir Habitat Enhancement
• Fish Ecology

Statement dc:rights

• Copyright 2022 Carly Fenstermacher

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/117843

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F117843